In Italy, a clown engineered a startling upset in February’s parliamentary elections, when the Five Star Movement, a band of political novices led by comedian Beppe Grillo, took more votes than long-established mainstream parties. In the U.K., “a collection of clowns” — in the dismissive phrase of veteran Conservative Cabinet Minister Ken Clarke — has just delivered a similar shock to the three large parties that have dominated Westminster politics for the best part of a century.

With counting still under way in some of the 34 municipalities in England and Wales that held elections on May 2, the UK Independence Party (UKIP), founded in 1993 and for many years more adept at infighting than at fighting elections, appears to have snatched a big chunk of seats on local councils and almost a quarter of the popular vote. A parliamentary by-election, held the same day to fill the South Shields seat vacated by former Foreign Secretary David Miliband, gave UKIP another triumph: not the Westminster seat that Britain’s first-past-the-post electoral system makes hard for any upstart party to win, but the satisfaction of pushing David Cameron’s governing Conservatives and their Liberal Democrat coalition partners into distant third- and seventh-place finishes respectively. Miliband’s Labour Party, now under the leadership of his brother Ed, held the seat, its majority also sharply reduced as UKIP’s message resonated with its blue-collar voters too.

That message bears a striking resemblance not only to the Five Star Movement’s manifesto but also to the platforms of many other once insignificant parties that are making a mark in European politics. This isn’t just about the desire to kick big, unresponsive parties where it hurts, though it’s certainly that. UKIP, in common with Grillo’s party and the others, is campaigning for tighter immigration controls, smaller government and, above all, a repatriation of powers from the European Union. These are ambitions that would not look out of place in a Conservative manifesto — and as Nigel Farage, UKIP’s jovial leader pointed out during a recent lunch with Westminster journalists, some Thatcherites, including the original Thatcherite, might feel more at home in UKIP than in today’s Conservative Party. “I cannot believe that a young Margaret Thatcher leaving Oxford [University] today would join the Conservative Party led by David Cameron. I think she’d come and get involved in UKIP and no doubt topple me within 12 months or so,” he said.

A Conservative Party led by Margaret Thatcher might conceivably take a more consistently Euroskeptic line than Cameron’s Tories and so stanch the flow of support to UKIP. But Thatcher herself would almost certainly stop short of UKIP’s central aim, to pull Britain out of the E.U. Europe has moved on since the Iron Lady wielded her handbag against its growing sway, and as Cameron took care to emphasize in a pivotal Jan. 23 speech, British businesses expect unfettered access to the E.U.’s single market:

If we leave the EU, we cannot of course leave Europe. It will remain for many years our biggest market, and forever our geographical neighbourhood. We are tied by a complex web of legal commitments. Hundreds of thousands of British people now take for granted their right to work, live or retire in any other EU country. Even if we pulled out completely, decisions made in the EU would continue to have a profound effect on our country. But we would have lost all our remaining vetoes and our voice in those decisions.

Cameron used his speech to promise Britons an in-out referendum on Europe if the Conservatives win an outright majority at the next elections. For now the Conservatives rely on the votes of their passionately Europhile Liberal Democrat partners who are unlikely to help them anchor Cameron’s promise in legislation. Meanwhile the upsurge in support for UKIP is, with no small irony, eroding the prospect for a Tory majority and its concomitant chance to vote Britain out of the E.U.

So it’s not clear that UKIP’s success brings Britain closer to leaving the E.U., any more than it’s clear what, exactly, the Five Star Movement means for Italy. The same calculations, and confusions, exist across Europe. Economic turbulence and political stasis have combined to roil establishments and open the door to Euroskeptic populists even in countries that have been historically ardently pro-Union.

A brand new party in Germany, the Alternative für Deutschland, is winning as much as 27% support in opinion polls. It’s unlikely to perform so strongly in the voting booth, but it has more than a fighting chance of polling above the 5% threshold necessary to win seats when the country holds federal elections in September. Elsewhere in Europe, hard-right parties are benefiting from anger at European and national institutions. In Finland, the anti-immigration True Finns have been the largest opposition party since 2011. Matthew Goodwin, an associate fellow at London’s foreign-affairs think tank Chatham House, describes the situation as “a perfect storm of parties that are trying to tap into that popular discontent with the established elite.”

The elite in many countries is responding by aping the populism and policies of their smaller rivals. Coalitions are fracturing, party discipline is fraying. The big parties are foolish to dismiss UKIP, the Five Star Movement and other small, burgeoning parties as clowns. But European politics has never looked more like a circus.